This invention relates to brazed ceramic seals for use in lithium ion batteries.
A chemical battery case may act to prevent the positive and negative output devices from coming into contact, i.e., shorting. The battery case in its entirety also functions to contain and prevent leakage of battery materials such as an electrolyte. Moreover, the battery case itself must provide for mechanical strength to contain pressures originating from within the battery as well as to provide the mechanical strength for ordinary handling of the battery.
The invention includes a brazed ceramic ring that separates the positive and negative ends of the battery while still providing a leak-tight seal. The ceramic is aluminum oxide or zirconium oxide or zirconium oxide with 3% yttrium. The invention includes a brazing material, which is greater than 50% gold. The invention includes a titanium alloy case (Ti-6Al-4V) which is titanium with 6% aluminum and 4% vanadium as its major alloying elements. The case has the desirable properties of titanium such as high strength for a relatively low weight; and the case has the requisite ability and electro-activity to be used as a positive current carrying element where the battery""s positive electrode exhibits more than 3.5 V vs. Li/Li+.